Department of Zoology, University of Melbourne, Parkville, Vic 3010, Australia.
J Fish Biol. 2012 May;80(6):2281-301. doi: 10.1111/j.1095-8649.2012.03283.x. Epub 2012 Apr 18.
This study tested the hypothesis that variable freshwater flow in the Gippsland Lakes, Australia, influences the location and extent of environmental conditions suitable for spawning and larval development of black bream, Acanthopagrus butcheri. Freshwater flow had a large influence on the salinity and level of stratification (difference between bottom and surface salinity) in the Gippsland Lakes. Freshwater flows throughout this study varied from no or low flows through to major flooding in 2007. Eggs of A. butcheri were found in similar concentrations throughout the lakes and rivers. More than 99% of larvae, however, were collected from within rivers, with very few larvae being collected from the lakes. A comparison of two spawning seasons revealed that the year with higher freshwater flows also had greater spawning activity and higher concentrations of larvae. Interestingly, there was a significant relationship between the distribution of eggs and larvae with the level of stratification. The highest concentrations of larvae occurred at sites with a difference in bottom and surface salinities of 15-20. This study demonstrates that despite A. butcheri spawning in the lakes and rivers, it is only locations with a halocline that function as larval nursery habitat.
本研究检验了这样一个假设，即澳大利亚吉普斯兰湖（Gippsland Lakes）淡水流量的变化会影响黑鲈（Acanthopagrus butcheri）产卵和幼鱼发育的环境条件的位置和范围。淡水流量对吉普斯兰湖的盐度和分层（底层和表层盐度之间的差异）水平有很大影响。在本研究中，淡水流量从无或低流量到 2007 年的大洪水不等。A. butcheri 的鱼卵在湖泊和河流中都有相似的浓度。然而，超过 99%的幼鱼是在河流中收集的，只有极少数幼鱼是从湖泊中收集的。对两个产卵季节的比较表明，淡水流量较高的年份产卵活动也较多，幼鱼浓度也较高。有趣的是，卵和幼虫的分布与分层水平之间存在显著的关系。幼虫浓度最高的地方是底层和表层盐度差为 15-20 的地方。本研究表明，尽管 A. butcheri 在湖泊和河流中产卵，但只有具有盐跃层的地方才能作为幼鱼育肥栖息地。
